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Action

Final Rule.

Summary

The FAA is superseding an existing airworthiness directive (AD) for Pratt Whitney (PW) JT8D-209, -217, -217A, -217C, and -219 series turbofan engines. That AD currently requires torque inspection of the 3rd stage and 4th stage low pressure turbine (LPT) blades for shroud notch wear and replacement of the blade if wear limits are exceeded. This AD continues to require those torque inspections at shorter inspection intervals of the refurbished 3rd stage and 4th stage LPT blades, but the same or longer inspection intervals of the new 3rd stage and 4th stage LPT blades, for shroud notch wear and replacement of the blade if wear limits are exceeded. This AD also requires replacing LPT-to-exhaust case bolts and nuts with bolts and nuts made of Tinidur material. This AD results from reports of 194 blade fractures since 1991, with 37 of those blade fractures resulting in LPT case separation, and three reports of uncontained 3rd stage and 4th stage LPT blade failures with cowl penetration. We are issuing this AD to prevent an uncontained blade failure that could result in damage to the airplane.

You can get the service information identified in this AD from Pratt Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-8770, fax (860) 565-4503.

You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA. You may examine the service information, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

The FAA proposed to amend 14 CFR part 39 with a proposed airworthiness directive (AD). The proposed AD applies to Pratt Whitney (PW) JT8D-209, -217, -217A, -217C, and -219 series turbofan engines. We published the proposed AD in the Federal Register on August 16, 2004 (69 FR 50346). That action proposed to require torque inspections of the 3rd stage and 4th stage LPT blades for shroud notch wear and replacement of the blade if wear limits are exceeded. That action also proposed to require replacing the LPT-to-exhaust case bolts and nuts with bolts and nuts made of Tinidur material.

You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location.

One commenter proposes to use a radioisotope inspection procedure, which they have developed and was approved as an alternative method of compliance (AMOC) for a previously issued AD. The commenter states that this inspection method is more reliable than the torque inspections mandated in this AD and provides an equivalent level of safety. The FAA does not agree. The commenter did not provide data to substantiate the claim of an equivalent level of safety as it relates to the revised inspection intervals. The commenter's proposal is also operator-specific and does not provide literature for the rest of the fleet. The FAA will evaluate a request for an AMOC that includes data substantiating that an acceptable level of safety is maintained using this procedure.

Another commenter states that the costs of compliance are underestimated. The commenter requests that we consider the costs of numerous parts removed when complying with this AD. The FAA does not agree. The indirect costs associated with this AD are not directly related to the required actions, and therefore, are not addressed in the economic analysis for this AD. A finding that an AD is warranted means that the original engine design no longer achieves the level of safety specified by related airworthiness requirements and that other required actions are necessary.

Another commenter states that the costs of compliance are underestimated. The commenter states that the cost of turbine blades and cost of labor to replace the blades when complying with this AD should be considered. The FAA agrees. We estimate that 10% of the blade sets will fail the inspection per year and will require replacement. Therefore, the estimated cost of turbine blades and labor to replace the blades is added to the total cost of the AD to U.S. operators to perform initial torque inspection and bolt and nut replacement.

Another commenter requests that the identification of the superseded AD be clarified. The FAA does not agree. The fact that this AD supersedes AD 99-27-01 is clearly stated in the compliance section of this AD. Although AD 99-22-14 requires replacement of the LPT-to-exhaust case bolts and nuts, that AD primarily addresses installation of high pressure turbine (HPT) containment hardware. Further, a notice of proposed rulemaking was published in the Federal Register on July 15, 2004 (69 FR 42356), which moves the requirement to replace the LPT-to-exhaust case bolts and nuts from AD 99-22-14 to this AD.

Another commenter requests that this AD include a reference to NDIP-622, Revision D. The FAA does not agree. We assume that the commenter intended tosay NDIP-662, Revision D and not NDIP-622, Revision D. This AD already references PW ASB No. JT8D A6224, Revision 5, which specifies the use of NDIP-662, which is included as an Appendix in the ASB. Because all pages of NDIP-662, Revision D, are included in the ASB, a clarification to the reference and a change to this AD are not necessary.

Request To Define “Accessibility to the LPT-to-Exhaust Case Bolts” Back to Top

Another commenter requests that this AD include a definition of the statement “accessibility to the LPT-to-exhaust case bolts” and that the definition match the one provided in PW SB 6455. The FAA agrees. A definition of “accessibility to the LPT-to-exhaust case bolts” is included in this AD.

Another commenter states that there is an overlap between the inspection torque readings in the tables providing the repetitive torque inspection intervals. For example, one range in Table 3 states “* * * but greater than or equal to 10 LB-IN (1.130 N.m).” Another range in Table 3 states “Less than or equal to 10 LB-IN (1.130 N.m) * * *”. A single value cannot have two different requirements. The FAA agrees. The affected tables are corrected in this AD.

Another commenter proposes to inspect only the turbine blades of the LPT stage that fails the torque check inspection. Also, the commenter proposes that the requirement to inspect the turbine blades of the other LPT stages should be suggested rather than mandated as proposed in the AD. The FAA agrees. This AD clarifies the information about how to return an engine to service. In addition, this AD clarifies the information about how the repetitive inspection intervals may be reset.

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

There are about 2,345 PW JT8D-200 series turbofan engines of the affected design in the worldwide fleet. We estimate that 1,143 engines installed on airplanes of U.S. registry are affected by this AD. We also estimate that it will take about 1 work hour per engine to perform the torque inspection and 1 work hour per engine to perform the bolt and nut replacements. The average labor rate is $65 per work hour. It is estimated that 10% of the blade sets will fail the inspection per year and will require replacement. The average cost for a new blade set is $72,500. The new blades take about 23 work hours to install. Based on these figures, the annual replacement cost of the AD to U.S. operators is $8,584,020. The required bolts and nuts will cost about $1,734 per engine. Based on these figures, we estimate the total annual cost of this AD to U.S. operators to perform initial torque inspection and bolt and nut replacement to be $10,565,982.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the National Government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 98-ANE-80-AD” in your request.

(d) This AD results from reports of 194 blade fractures since 1991, with 37 of those blade fractures resulting in low pressure turbine (LPT) case separation, and three reports of uncontained 3rd stage and 4th stage LPT blade failures with cowl penetration. We are issuing this AD to prevent an uncontained blade failure that could result in damage to the airplane.

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

Initial Torque Inspection for JT8D-209, -217, and -217A Engines Back to Top

(f) For JT8D-209, -217, and -217A engines, perform the initial torque inspection of 3rd and 4th stage LPT blades for shroud notch wear. Use the procedures described in Accomplishment Instructions, part 1, paragraphs 1. through 3. of PW Alert Service Bulletin (ASB) No. JT8D A6224, Revision 5, dated June 11, 2004, at the applicable threshold in the following Table 1:

Table 1.—Initial Torque Inspection Threshold for JT8D-209, -217, and -217A Engines Back to Top

(i) JT8D-209, -217, and -217A engines removed from service may be returned to service after a detailed inspection and repair or replacement for all blades, of the failed stage, that exceed Engine Manual limits is done. Information on repairing or replacing turbine blades can be found in Sections 72-53-12 through 72-53-13 of the JT8D-200 Engine Manual, Part No. 773128.

(j) For JT8D-217C and -219 engines, perform the initial torque inspection of 4th stage LPT blades for shroud notch wear. Use the procedures described in Accomplishment Instructions, Part 2, Paragraphs 1. through 3. of PW ASB No. JT8D A6224, Revision 5, dated June 11, 2004, at the applicable threshold in the following Table 4:

Table 4.—Initial Torque Inspection Threshold for JT8D-217C and -219 Engines Back to Top

(m) JT8D-217C and -219 engines removed from service may be returned to service after a detailed inspection and repair or replacement for all blades, of the failed stage, that exceed Engine Manual limits is done. Information on repairing or replacing turbine blades can be found in Sections 72-53-12 through 72-53-13 of the JT8D-200 Engine Manual, Part No. 773128.

(q) At next accessibility to the LPT-to-exhaust case bolts, part number (P/N) ST1315-15, and nuts, P/N 4023466, replace bolts and nuts with bolts and nuts made of Tinidur material. Information on replacing the bolts and nuts can be found in PW SB No. 6455, dated January 15, 2004.

(r) For the purpose of this AD, refurbishment is defined as restoration of either the shrouds or blade retwist or both, per the JT8D-200 Engine Manual, Part No. 773128.

(s) For the purpose of this AD, “As-Cast” refers to blades that were machined from new castings and “Modified” refers to blades that were derived from the pre-SB No. 6090 configuration.

(t) For the purpose of this AD, “accessibility to the LPT-to-exhaust case bolts” refers to when the engine is disassembled sufficiently to give access to the LPT-to-exhaust case bolts, which is whenever the inner turbine fan ducts are removed.

(v) You must use Pratt Whitney (PW) Alert Service Bulletin (ASB) No. JT8D A6224, Revision 5, dated June 11, 2004, to perform the inspections required by this AD. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You can get a copy from Pratt Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-8770, fax (860) 565-4503. You can review copies at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.